Error if headphones and mic are not enabled both.

Description

Hello,
The example of an error you can see here:
https://forums.virtualbox.org/viewtopic.php?f=6&t=42017
I have the very same.
My host is Windows 7 x86.
My guest is Windows XP x86.
The part of log you should be interested in is:
00:00:00.927 Audio: Trying driver 'dsound'.
00:00:00.941 DSound: Could not initialize DirectSoundCapture
00:00:00.942 Audio: set_record_source ars=0 als=0 (not implemented)
00:00:00.943 AC97: WARNING: Unable to open PCM IN!
00:00:00.943 AC97: WARNING: Unable to open PCM MC!
00:00:00.943 VM: Raising runtime error 'HostAudioNotResponding' (fFlags=0x0)

Full log attached as well.

This problems solves once I plug BOTH my mic and my headphones back the host machine (If only headphones will be pluged in error will still remain).
Log with plugged mic and headphones are attached too.
File with VM info attached as well.
Please take a look at it and let me know if you need any additional details.
Thanks.